Arc 1:Chapter 27

The bickering of the two continued until a sound akin to a massive body being dragged resounded at the inner part of the trees covered mountain... along with it followed various howls and growls of animals, probably mutant ones.

Martin glanced at the source of the disturbing sound, his grip at his gun tightened noticeably, as unease bloomed inside him.

Although he expected it, he still couldn't believe the fact that that walker truly has its trump card. However, compared to that time, the walker which led the mutants seemed in an incomplete evolution. Perhaps, it is only beginning its metamorphosis. Also, seeing as the power and simple attacking movements of the undead and mutants, the thinking of the boss seemed to be limited to its natural way of thinking. It was not experienced enough because it hasn't met that many of a humans specializing in combat such as them. They hadn't met a prey that cannot be easily hunted.